QRFP-43

Where it comes from

Made in

A few hypothalamic neurons (ventromedial and lateral), plus testis and fat; its receptor sits in retina and bone

Sent out by

Fasting raises it

Acts on

• Hypothalamic feeding circuits
• Osteoblasts
• Islets (insulin)
• Fat cells
• Adrenal (aldosterone)

What it does

• Drives feeding and fat storage when given centrally; mice held to a matched ration still gained fat ¹
• Mice lacking its receptor have thin bones, and the peptide releases aldosterone from adrenal cells ³
• Part of the brain’s long-term control of body weight; its neurons drive a hibernation-like state in mice, though the peptide itself is not needed for that ²

In medicine

• No medicine copies it or blocks it, and it is not measured in people
• Its receptor has no ligand in clinical use. The interest in it is in bone and in body weight, and both rest on mouse work ³

Beyond the body’s own use

• Nothing containing it is in trials, approved or obtainable outside the laboratory
• Its neurons are the striking part. Switching them on drops a mouse into a hibernation-like state, with body temperature and metabolic rate down for days; mice that cannot make the peptide still do it, so the circuit rather than the peptide carries the effect ²
• What is unknown is which of the gene’s two peptides does the work. QRFP-43 and 26RFa act at the same receptor, and nearly all the feeding and glucose work uses the shorter one ³